Refrigeration expansion valve apparatus



July 17, 1956 c. B. BoLEs REFRIGERATION EXPANSIN VALVE APPARATUS FiledApril 18, 1952 INVENTOR.

Chalmers B. Boles BY/ZH/Lamwv WZ@ United States Patent O REFRIGERATIONEXPANSION VALVE APPARATUS Chalmers B. Boles, Dayton, Ohio, assigner toGeneral Motors Corporation, Dayton, Ohio, a corporation of DelawareApplication April 18, 1952, Serial No. 283,011

8 Claims. (Cl. 236-92) This invention relates to refrigerating apparatusand more particularly to expansion valves with a limiting device forpreventing excessive loads.

Recently there has been introduced on the market thermostatic expansionvalves with pressure limiting devices which collapse to assist theclosing of the valve when a predetermined pressure is attained in thevalve outlet.

lt is an object of my invention to provide a thermostatic expansionvalve with a limiting device which expands instead of collapses todirectly close the valve.

lt is another object of my invention to provide a thermostatie expansionvalve with a small unitary readily replaceable limiting device located achamber of the Valve which is readily opened.

These objects are attained by providing a thermostatic expansion valvein which the valve element is carried directly by a sealed capsulelocated in the valve outlet chamber. During normal operation of theValve the valve element is carried in retracted position and the capsuleis bodily moved by the usual combined temperature and pressureresponsive element of the valve as if no limiting device were included.This results in a normal refrigerant ow from the condenser to theevaporator. When the temperature and pressure is reached in the valveoutlet chamber at which it is desired to limit the flow through thevalve, the sealed capsule expands to move the Valve element into ortowards engagement with its seat to close or limit the ilow through thevalve.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings, wherein a preferred form of the present invention is clearlyshown.

In the drawings:

Figure l is a vertical sectional view through an expansion valveembodying one form of my invention;

Figure 2 is an enlarged sectional view of the pressure limiting capsuleand fragments of adjacent parts; and

Figure 3 is a fragmentary enlarged section of the thermostatic chamberand diaphragm.

Referring now to the drawings and more particularly to Figure l there isshown a valve body having an inlet 22 provided with a are connection forconnection with a refrigerant condenser. The valve body 2t) is alsoprovided with an outlet 24 provided with a flare connection forconnection with a refrigerant evaporator. The inlet 22 connects with aninlet passage provided with a conical straining screen 26 which leads toa vertical passage provided along the axis of the valve body 20. Thisvertical passage connects directly with a valve seat insert 27 which isthreaded into the lower end of the vertical passage and is provided witha valve seat at the outlet of the passage. The passage dischargesdirectly into a valve chamber 28 within the valve body 20. This valvechamber 28 has a side outlet connecting with the are connection 24 whichin turn connects to the refrigerant evaporator.

ICC

At the top of the valve body 20 there is provided a diaphragm 30. Theouter rim of the diaphragm 30 is held in place by the downwardly turnedflange of a cap member 32 secured in place by a bent over upwardlyfacing flange 34 provided at the top of the valve body 20. The top ofthis cap member 32 is connected by a capillary tube 36 with a thermostatbulb 38. The cap 32, the capillary tube 36 and the bulb 38 may becharged with a thermostatic liquid or a volatile liquid or vapor, butpreferably the bulb 38 is provided with a charge of activated charcoaland it together with the capillary tube 36 and the cap member 32 areprovided with a charge of a permanent gas such as carbon dioxide whichis adsorbed and evolved from the activated charcoal in the bulb 38according to the temperature of the bulb 38. According to presentrefrigeration practices it is customary to clamp the bulb 33 in thermalexchange relationship with the outlet portion or suction conduit of therefrigerant evaporator. When the evaporator outlet temperature is highas prevails when the system is shutdown for a considerable length oftime the diaphragm 30 will be depressed by the pressure of the gas orvapor in the cap 32. This would cause an ordinary expansion valve to beheld wide open to provide an abnormally high pressure in the evaporatorto impose an abnormally heavy load upon the compressor.

eneath the diaphragm 30, there is a metal diaphragm pad 46 which restsupon three pins each designated by the reference character 42. Thesepins 42 extend into the chamber 23 and their lower ends engage theupwardly facing recessed surface of a valve supporting means 44 locatedwithin the chamber 28. The valve supporting means 44 is provided with aflexible diaphragm 46. The outer portion of this diaphragm 46 is held byan upwardly facing ange 48 of an insert 50 provided in the bottom of thevalve supporting member 44. The flange 48 holds the outer portion of thediaphragm 46 in contact with a. shoulder in a diaphragm chamber withinthe central portion of the valve supporting means 44. The diaphragm 46and the member 50 are sealed to the valve supporting means 44 by adownwardly extending rim 52 upon the valve supporting means 44 which isrolled inwardly to accomplish the sealing. This sealing may be madedoubly sure by the use of solder.

Mounted upon the upper face of the diaphragm 46 is a anged valve element54 which protrudes through a centrally located aperture in the top ofthe diaphragm chamber in the valve supporting means 44. The uppermostportion of the valve element 54 is provided with a ball 56 which engagesthe valve seat insert 27 to close the inlet passage in the valve body20. Under normal conditions, the valve element S4 and the ball 56 willbe held in retracted position within the valve supporting means 44 withthe central portion of the diaphragm 46 resting upon a centrally locatedstop pad 58 upon the bottom of the diaphragm chamber. According to myinvention the chamber formed beneath the diaphragm 46 is sealed. It issubject to the pressure of the refrigerant in the valve chamber 28 whichhas access to the upper surface of the diaphragm 46 through the openingin the top of the valve supporting means through which projects the topof the valve element 54. This pressure tends to keep the valve elementretracted within the valve supporting means 44 with the diaphragm 46 inengagement with the stop pad 58.

To provide my valve with a pressure limiting feature, the chamberbeneath the diaphragm 46 is charged with a temperature responsiveexpansible medium having a steeper pressure-temperature curve than therefrigerant controlled by the valve. Preferably this chamber is chargedwith the vapor of a volatile liquid having a steeperpressure-temperature curve than the refrigerant being used. This chamberis charged through a charging tube 59 and is then sealed when the properamount of charge is applied. if desircd'the chamber beneath thediaphragm 46 canbe charged with an absorbentV such as activated charcoaland a permanent' gas such as carbon dioxide. If the pressure of theselectedV volatile liquid placed in the chamber beneath the diaphragm 46is appreciably higher than the pressure of the refrigerant which passesthrough the chamber 28 at which it is desired to limit thetlow throughthe valve, there is provided a spring 60 having its upper outer portionbearing against the valve supporting means and having its lower innerportion bearing against the topY of the flange on the valve element 54.This spring 60` may be of any suitable shape but preferably is in theform of a dished ring which may have inwardly extending fingers restingupon the top ofthe flange of the valve element 54. With suchanarr'angement,4 when the pressure and temperature is reached in theoutlet chamber 28 at which the limiting action is desired, the pressurebeneath the diaphragm will be great enough to move the valve membertoward or into engagement with the valve seat insert 27.

As specic examples of the invention, it will be assumed that in twodifferent applications it is desired to reduce the flow through thevalve to a minimum when the refrigerant within the chamber 28 rises totemperatures of F. and 38 F. These limiting temperatures would besuitable for frozen food systems and beveragecooling systemsrespectively. Diiluorodichloromethane (F-12) and methyl chloride (CHaCl)have been selected as examples of refrigerants which are suitable foruse in the refrigerating system. The following refrigerants are selectedas examples of the vapors which may be used in the diaphragm chamber ofthe valve supporting means 44 since in the range of useful operatingtemperatures in which the valve operates they have steeperpressure-temperature curves than F-12 and methyl chloride:

Monochlorodiiluoromethane (F-22), ammonia, perfluoropropane (CsFa)(F-218) and pentauoromonochloroethane (CzClFs) (F-l 15).

The following table indicates the pressures of these refrigerants andvapors at 10 F. and 38 F. as well as the differences `in the pressuresbetween each of these vapors and each of the refrigerants:

Table of refrigerant pressures and differences In each case the pressureis higher than the pressures of the F-12 and methyl chloride. Thisdifference in pressures must be counteracted and substantially exactlyequaled by the spring force of the diaphragm 46 and the spring 60. For afrozen food installation requiring a valve with a limiting actioneffective at about 10 F., with F-12 as the refrigerant if the effectivearea of the diaphragm 46 is about .11 sq. in. then a spring force ofabout 2 pounds would be required with F-22, while spring forces of onepound would be required for ammonia; 1.35 pounds would be required forF-218 and 1.4 pounds would be required for F-115. This spring forcewould be the force of the spring 60 and the diaphragm 46 in a positionnear the uppermost position.

With any of these examples, as long as the temperature within the valvechamber is an adequate amount below 10 F., there will be no limitingaction because below about 10 F. the pressure of the refrigerant uponthe diaphragm 46 plus the spring force of the spring 60 and thediaphragm 46 is always greater than the pressure of the vapor within thediaphragm chamber in the valve supporting means 44 so that the diaphragm46 will be pushed down against the pad 58. This must be true since ifthe balanced condition is about 10 F. and the vapor has a steeperpressure-temperature curve than the refrigerant, the refrigerant andallied spring forces will be greater than the force of the vapor below10 F. and less than the force of the vapor above 10 F. It follows fromthis that above 10 F., the vapor pressure within the diaphragm chamberin the valve supporting means 44 always will be greater than theopposing refrigerant pressure and the allied spring forces so that thediaphragm 46 will be forced upwardly to move the ball 56 toward or intoengagement with the valve seat in thc insert 27.

As another example, assume for a beverage cooler installation it isdesired to set the valve so that its maximum limiting action would bereached at 38 F. The pressures of these different vapors at 38 F. areindicated in the table as wel] as the difference in pressure betweenthese particular vapors and F-12 at 38 F. Again we assume that thediaphragm 46 has an effective area of .ll sq. in. A downward springforce of the diaphragm 46 and the spring 60 would be required. For F-22this force would be 3.4 pounds, for ammonia 2.3 pounds, for F-Zl 8 2.25pounds and F-1l5 2.4 pounds. It appears that for these latter three oneparticular spring arrangement would be satisfactory and this could beset at about 2.3 pounds.

Instead of F-12 as the refrigerant in the system, methyl chloride couldbe used as shown in the table. Methyl chloride at 10 F. would have apressure of 8.9 pounds and at 38 F. it would have a pressure of about 27pounds. The difference in pressure between any one of the refrigerantsin the capsule would be greater as illustrated by the ditferenec inpressure noted in the table. The spring force required at 10 F. would be2.66 pounds for F42, 1.65 pounds for ammonia, 1.94 pounds for F-218 and2.06 pounds for F-1l5. With methyl chloride at 38 F., a spring force of4.33 pounds would be required for F-22, 3.17 pounds with ammonia, 3.18pounds with F-218 and 3.35 pounds with F-115.

For other selected limiting temperatures different spring forces couldbe provided. These spring support assemblies could be made in sets fordifferent refrigerants and different limiting temperatures andpressures. They would be interchangeable in the chamber 28. They couldbe readily removed and inserted from the chamber 28 by removing thethreaded cap member 62 which is threaded into the open end portion ofthe chamber 28. This cap member 62 has a threaded adjusting screw 64therein which engages a spring retainer 64 provided at the lower end ofthe valve closing spring 66. The upper end of this valve closing spring66 rests against the bottom of the member 50 and holds the springsupport assembly 44 in engagement with the three pins 42.

The chamber 28 may be connected by a passage 68 with the chamber beneaththe diaphragm 30 which contains the pad 40. Otherwise the passagesthrough which the pins 42 extend may be relied upon for this purpose.The chamber beneath the diaphragm 30 may also be connected to the outletof the evaporator if desired. The screw 64 may be turned to adjust thetension ofthe spring 66 so as to adjust the pressure and temperature atwhich the valve normally opens. The lower end of the screw 64 isenclosed by a cap nut 70 to complete the sealing of the chamber 28.

While the form of embodiment of the invention as herein disclosed,constitutes a preferred form, it is to be understood that other formsmight be adopted, as may come within the scope of the claims whichfollow.

What is claimed is as follows:

1. An expansion valve for controlling the flow of a refrigerantincludinga valve body having an inlet and an outlet, a valve means forcontrolling the ow of refrigerant from'said inlet to said outlet, aflexible diaphragrnmeans' associated with said valve body andhaving'operative connecting means for moving said valve means to openposition, means fordeflecting said diaphragm means to operate said valvemeans, said valve means including a second bodily movable sealeddiaphragmfmeans and a valve member carried by and operated by saidsealed diaphragm means, said sealed diaphragm means and said valvemember constituting principal parts of and being bodily'movable with thevalve means and said flexible diaphragm means, adjusting meansassociated with said Valve body, spring means extending between saidadjusting means and said valve means, and a temperature responsiveexpansible medium within said sealed diaphragm means having a greaterrise vin pressure for a corresponding rise in temperature than therefrigerant controlled by the valve, said valve member having aconnection to said diaphragm means for movement toward valve closingposition upon expansion of the second diaphragm means within the samerange of operating temperatures.

2. An expansion valve for controlling the flow of a refrigerantincluding a valve body having an inlet and an outlet, a valve means forcontrolling the flow of refrigerant from said inlet to said outlet, aflexible diaphragm means associated with said valve body and havingoperative connecting means for moving said valve means to open position,means for dellecting said diaphragm means to operate said valve means,said valve means including a second bodily movable sealed diaphragmmeans and a valve member carried by and operated by said sealeddiaphragm means, said sealed diaphragm means and said valve'memberconstituting principal parts of and being bodily movable with the valvemeans and said flexible diaphragm means, adjusting means associated withsaid valve body, spring means extending between said adjusting means andsaid valve means, and a temperature responsive expansible medium withinsaid sealed diaphragm means having a greater rise in pressure for acorresponding rise in temperature than the refrigerant controlled by thevalve within the same range of operating temperatures, said valve meansalso including spring means for biasing said second diaphragm means,said valve member having a connection to said diaphragm means formovement toward valve closing position upon expansion of the seconddiaphragm means.

3. An expansion valve for controlling the ow of a refrigerant includinga valve body having an inlet and an outlet, a valve means forcontrolling the flow of refrigerant from said inlet to said outlet, aflexible diaphragm means associated with said valve body and havingoperative connecting means for moving said valve means to open position,means for deflecting said diaphragm means to Operate said valve means,said valve means including a second bodily movable sealed diaphragmmeans and a valve member carried by and operated by said sealeddiaphragm means, said sealed diaphragm means and said valve memberconstituting principal parts of and being bodily movable with the valvemeans and said flexible diaphragm means, adjusting means associated withsaid valve body, spring means extending between said adjusting means andsaid valve means, and a temperature responsive expansible medium withinsaid sealed diaphragm means having a greater rise in pressure for acorresponding rise in temperature than the refrigerant controlled by thevalve within the same range of operating temperatures, said valve meansalso including a stop arrangement for limiting the movement of the valvemember, said valve member having a connection to said diaphragm meansfor movement toward valve closing position upon expansion of the seconddiaphragm means.

4. A thermostatic expansion valve for controlling the ow of arefrigerant including a valve body having an inlet and an outlet and achamber connected to the outlet, said body having a valve seat locatedbetween said chamber and said inlet, a thermostatic operating meanslocated on one side of said valve seat, a valvev supporting'meanslocated in said chamber on the opposite side of the valve seat from saidthermostatic operating means,v a sealed diaphragm means located uponsaid supporting means, a valve member positively mounted on the face ofsaid sealed diaphragm means nearest said valve seat for movement towardthe valve seat upon expansion of the sealed diaphragm means, a movementtransmitting means extending from said thermostatic means to said valvesupporting means, said sealed diaphragm means being charged with avolatile liquid having a greater rise in pressure for a correspondingrise in temperature than the refrigerant within the same range ofoperating temperatures, said valve member having a connection to saiddiaphragm means for movement toward valve closing position uponexpansion of the second diaphragm means for expanding said diaphragmmeans above a predetermined refrigerant temperature to reduce the amountof valve opening.

5. A thermostatic expansion valve for controlling the flow of arefrigerant including a valve body having an inlet and an outlet and achamber connected to the outlet, said body having a valve seat locatedbetween said chamber and said inlet, a thermostatic operating meanslocated on one side of said valve seat, a valve supporting means locatedin said chamber on the opposite side of the valve seat from saidthermostatic operating means, a sealed diaphragm means located upon saidsupporting means, a valve member positively mounted on the face of saidsealed diaphragm means nearest said valve seat for movement toward thevalve seat upon expansion of the sealed diaphragm means, a movementtransmitting means extending from said thermostatic means to said valvesupporting means, said sealed diaphragm means being vcharged with avolatile liquid having a greater rise in pressure for a correspondingrise in temperature than the refrigerant within the same range ofoperating temperatures for expanding said diaphragm means above apredetermined refrigerant temperature to reduce the amount of valveopening, and adjustable spring means bearing upon said supporting meansfor opposing said thermostatic operating means.

6. A thermostatic expansion valve for controlling the flow of arefrigerant including a valve body having an inlet and an outlet and achamber connected to the outlet, said body having a valve seat locatedbetween said chamber and said inlet, a valve supporting means located insaid chamber adjacent said valve seat, a diaphragm located upon the sideof the valve seat opposite said valve supporting means, said valve bodyhaving a shallow chamber adjacent said diaphragm, a cap member enclosingsaid diaphragm, said cap member and said diaphragm being sealed to saidvalve body around said shallow chamber, a thermostat bulb connected tosaid cap member, push pins extending from said shallow chamber throughthe valve body to said valve supporting means for moving the valvesupporting means in accordance with the movement of the diaphragm, saidvalve supporting means being provided with a shallow chamber facing saidvalve seat, a second diaphragm covering said shallow chamber and havingits edge portions sealed to said supporting means, a valve memberpositively supported upon the face of said second diaphragm nearest thevalve seat for engagement with said valve seat, said shallow chamber insaid supporting means being charged with a volatile liquid having agreater rise in pressure for a corresponding rise in temperature thanthe refrigerant within the same range of operating temperatures forexpanding said second diaphragm toward said valve seat above apredetermined refrigerant temperature to reduce the opening of thevalve.

7. A thermostatic expansion valve for controlling the ow of arefrigerant including a valve body having an inlet and an outlet and achamber connected to the outlet, said body having a valve seat locatedbetween said chamber and said inlet, a valve supporting means located insaid chamber adjacent said valve seat, a diaphragm located upon the sideof the valve seat opposite said valve supporting means, saidk valve bodyhavinga shallow chamber adjacent said diaphragm, a cap member enclosingsaid diaphragm, saidcapl member and said diaphragm being sealed to saidvalve body around said shallow chamber, a thermostat bulb connected tosaid cap member, push pins extending from said shallow chamber throughthe valve bodyito said valve supporting means for moving the valvesupporting means in accordance with the movement of the diaphragm, saidvalve supporting means being provided with a shallow chamber facing saidvalve seat, a second diaphragm covering said shallow chamber and havingits edge portions sealed to said supporting means, a valve memberpositively supported upon the face of said second diaphragm nearest thevalve seat for engagement with said valve seat, said shallow chamber insaid supporting means'being charged with a volatile liquid having agreaterv rise in pressure for a corresponding rise in temperature thanthe refrigerant within the same range of operating temperatures forexpanding said second diaphragm toward said valve seat above apredetermined refrigerant temperature to reduce the opening of thevalve, said supporting means being provided with a stop arrangementcooperating with said valve member to limit the movement of said valvemember.

8; A thermostatic expansion valve for controlling the ow of arefrigerant including a valve body having an inlet and an outlet and achamber connected to the outlet, said body having a valve seat locatedbetween said cham ber and said inlet, a valve supporting means locatedin said chamber adjacent said valve seat, a diaphragm located upon theside of the valve seat opposite said valve supporting means, said valvebody having a shallow chamber adjacent said diaphragm, a cap, memberenclosing said diaphragm, said cap member and said diaphragm beingsealed to said valve body around said shallow cham' ber, a thermostatbulb connected to said cap member, push pins extending from said shallowchamber through the valve body to said valve supporting means for movingthe valve supporting means in accordance withthe movement of thediaphragm, said valve supporting means being provided with a shallowchamber facing said valve seat, a second diaphragm covering said shallowchamber and having its edge portions sealed to said supporting means, avalve member positively supported upon the face of said second diaphragmnearest the valve seat for engagement with said valve seat, said shallowchamber in said supporting means being charged with a volatile liquidhaving a greater rise in pressure for a corresponding rise intemperature than the refrigerant within the same range of operatingtemperatures, `said valve member having a connection to said diaphragmmeans for movement toward valve closing position upon `expansion ofsecond diaphragm means for expanding said second diaphragm toward saidvalve seat above a predetermined refrigerant temperature to reduce theopening of the valve, said supporting means being provided with springmeans for biasing said second diaphragm.

References Cited in the file of this patent UNITED STATES PATENTS2,505,933 Aughey et al May 2, 1950 2,506,413 Dube May 2, 1950 2,511,565Carter June 13. 1950

